Hmm...I'm thinking these spoilers for episode 10 will explain this one from the promotional photos. But, I guess we'll have to wait to find out for sure. In the meantime, here they are, official spoilers for Glee episode 10, "Ballad":
Mr. Schuester has the Glee Club split up into pairs to sing their favorite ballad, but when one kid gets sick, he’s forced to step in and winds up in a sticky situation. Meanwhile, Finn (Cory Monteith) has dinner with Quinn’s parents (guest stars Gregg Henry and Charlotte Ross).